Re: postgre vs MySQL

On Thu, 13 Mar 2008, rrahul wrote:

> I see Mysql bosting for Google,Yahoo, Alcatel......

Sure they are. Do some reading on the Google installation. The blog list
at http://www.mysql.com/customers/customer.php?id=75 works as well as any.

The reality here is that Google was just about fed up with MySQL not
working well enough for them circa 2000, and what they ended doing is a
combination of customizing MySQL to add the features they needed along
with doing a large-scale replication job. They don't need any instance to
be reliable, they solve that problem with redundancy instead.

Look at http://code.google.com/p/google-mysql-tools/wiki/Mysql4Patches
They had to add multiple replication features and fix some tiny little
bugs, you know things like "Changed InnoDB to recover when InnoDB and
MySQL data dictionaries are inconsistent".*

Now, ask yourself this: do you have that level of resources? Are you
going to write your own recovery tool when MySQL bungles a commit and the
data dictionary is screwed up? If not, I wonder how much that Google has
managed to hack MySQL into a usable state for them should matter to you.

* Why does this data dictionary corruption happen in MySQL? Because the
data dictionaries (which they just call metadata), the most important
tables in the database, are still using a design that frankly is garbage.
See http://forge.mysql.com/w/images/0/0a/Mdl.pdf for details, it starts
with the cheery "Designed in the pre-transactional era of MySQL,
[metadata] has not had an overhaul or a clean up ever since then".

--
* Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD